Executive Summary
Investigation Purpose
In 1996, the Oregon Water Resources Department issued thirty-two ADR ground
water permits for primary and supplemental irrigation in the eastern Lost River
sub-basin. The permit conditions require the Department to decide whether the
permits will expire or can mature into certificates based upon the following:
A. River stage or Bonanza Big Springs flows are not significantly diminished by
use of water under each permit as determined by the Oregon Water Resources
Department, in consultation with the Bureau of Reclamation and Oregon
Department of Fish and Wildlife, using quantifiable groundwater and
hydrologic science that stands up to peer review;
B. Within two years of permit issuance for primary use, the
permittee/appropriator has submitted a plan to the Department indicating
potential economic sources for an alternative long-term water supply;
C. Periodic water level reports have been submitted; and
D. Excessively declining ground water levels have not occurred due to well use
as determined by the Oregon Water Resources Department, in consultation
with the Bureau of Reclamation and Oregon Department of Fish and Wildlife,
using quantifiable groundwater and hydrologic science that stands up to peer
review.
This investigation was conducted to address conditions A and D. That effort
necessitated advancing the state of knowledge about the ground water system.
Geography, Climate and Land Use
The 920 square mile ground water investigation area was limited to the eastern
portion of the Lost River sub-basin, east of Klamath Falls. The area includes the
Town of Bonanza and the communities of Dairy, Yonna, and Lorella.
Northwest trending uplands separate the interconnected Langell, Yonna, Poe, and
Swan Lake Valleys and Pine Flat lowlands. Annual average precipitation and
native vegetation indicate the sub-basin is semi-arid.
Agriculture is the dominant private land use. It includes cattle and sheep ranches,
dairies, and irrigated acreages. Irrigation water comes from surface and ground
water sources allocated by Oregon water rights. The U.S. Bureau of Reclamation
Klamath Project delivers most of the surface water used via irrigation districts. In
2002, about 225 ground water rights were valid for irrigation in the sub-basin.
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Geologic Framework (compiled from other investigations)
The geology of the upper Klamath basin and the eastern Lost River sub-basin is
complex. The upper Klamath basin is located in the transition area between the
Cascade Mountain and the Basin and Range physiographic provinces. The eastern
Lost River sub-basin is located within the Basin and Range province. The
province is characterized by long and narrow, north-south trending fault-block
mountains separated by broad basins filled with sedimentary rock and sediments.
The stratigraphy of the sub-basin consists of numerous units of basalt and
sedimentary rock and sediments. Many units are contemporaneous with complex
relationships. Water influenced the deposition of many units. Some units show
evidence of hydrothermal alteration or secondary mineralization that followed
deposition.
Geologically young (3.8 to 8.2 million years) basalt occurs throughout the subbasin as multiple layers with some sedimentary interbeds between layers. Unit
thickness ranges from less than 50 ft to approximately 2,000 ft. Individual flows
may be discontinuous and can vary in texture. Depositional environments range
from subaerial, to some interaction with water, to submerged. Some units show
gradations indicating they experienced multiple depositional environments. Most
exposed basalt occur in the uplands. In the valleys, basin fill sedimentary rock
and sediments bury the basalt units except at buttes.
Sub-basin sedimentary rock and sediments predominantly occur in the valleys as
lacustrine, fluvial, and volcaniclastic basin fill that overlies the basalt. The
thickness of the basin fill can range from a few feet to hundreds of feet. Some
basalt dikes, sills, and flows are found within the basin fill.
The general sub-basin geologic structure includes numerous north-northwest
trending and occasional east-west trending faults. Most of the faults vertically
offset geologic units creating upland blocks (horsts) with steep escarpments along
the fault. Down-dropped blocks (grabens) form valleys between the horsts.
Geologic History (compiled from Black, 2004)
The oldest exposed rocks in the sub-basin are late Miocene (7.32 and 8.18 million
year age dates) basalts found on Bryant Mountain and Gift Butte. They were
deposited as thin horizontal sheets erupted over subdued topography. The units
show interaction with water, and lacustrine sedimentary interbeds occur between
some flows. These flows are assumed to underlie the entire sub-basin.
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Master Basin and Range faulting commenced about 7 million years ago. This
started erosion of fully emplaced basalt units creating low hills and broad valleys.
Lacustrine mudstone and fluvial deltaic sandstone accumulated in the developing
basins during a period of volcanic inactivity. The mudstone came from volcanic
ash from nearby eruptive centers.
Volcanic activity in the sub-basin eventually resumed (5.4 million year maximum
age date, 4.6 to 3.8 million year age for most samples), and non-master faults that
produced buttes and other small uplands within the valleys commenced about 4.5
million years ago. Eruptions occurred along master graben-bounding faults and
within the basins. Flows erupted onto the sediments, flowed into the basins and
up against the basaltic highs, locally ponded, and/or interacted with water over
large areas.
More recently during the Pleistocene, pluvial Lake Modoc purportedly inundated
the sub-basin valleys in addition to the Upper Klamath Lake and Tule Lake
valleys. The lake elevation apparently fluctuated rising to a maximum elevation
of 4,240 ft. During this period, lacustrine deposition occurred within the lake,
Miller Creek formed a gravel delta as it flowed into the lake, and other alluvial
fans were deposited by other drainages. When Lake Modoc receded, it left
behind Upper Klamath Lake, Tule Lake, Alkali Lake, and Swan Lake.
Additionally, the Lost River was established. Subsequently, some sedimentary
deposition has occurred. No evidence has been found for volcanism occurring in
the sub-basin during the Pleistocene to the present.
Ground Water Occurrence
Water well reports indicate ground water occurs in both basalt and basin fill
sedimentary rocks and sediments. Despite the complex geology in the sub-basin,
sufficient hydraulic connection exists between water bearing zones in
predominantly basalt units to allow lumping them as undifferentiated basalt.
Additionally, sufficient hydraulic connection exists between water bearing zones
in predominantly basin fill sedimentary rock and sediment units to allow lumping
them as undifferentiated sediments.
Ground water in basalt and the overlying basin fill is generally hydraulically
interconnected, especially in Langell, Poe, and Yonna Valleys. Evidence includes
similar ground water elevations and ground water level trends. In Swan Lake
Valley and Pine Flat, ground water in the deeper portion of the basin fill has an
efficient (direct) hydraulic connection to ground water in the basalt below.
Ground water in the upper portion of the basin fill is either perched above deeper
ground water or has a high vertical gradient to deeper ground water. Evidence
includes anomalously high ground water elevations at a few wells surrounded by
wells showing much lower ground water elevations and different ground water
trends.
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Data indicate four sub-areas exist in the eastern Lost River sub-basin: south
Langell Valley, Lorella, Bonanza, and Swan Lake Valley to Poe Valley. In
addition, nine compartments exist within the Lorella sub-area and three
compartments exist in the Swan Lake Valley to Poe Valley sub-area adjoining the
central portion of the sub-area. The compartment boundaries are poorly defined,
but they likely correspond to buried geologic structures.
Ground Water Temperatures
The temperature range of ground water in basalt and the basin fill is similar. The
reported ground water temperatures for 157 wells completed in basalt range from
45 to 90oF. The reported ground water temperatures for 24 wells completed in
sediments range from 45 to 80oF. The higher temperatures indicate the presence
of water heated during deep circulation.
Hydraulic Properties of Basalt and Basin Fill
Water well reports indicate the hydraulic properties of the basalt and basin fill
generally differ. The reported yield of 199 wells completed in basalt range from 4
gal/min minimum to 5,500 gal/min maximum. The average and median yields are
1,470 and 1,500 gal/min respectively. The reported yield of 44 wells completed
in basin fill sediments range from 2 gal/min minimum to 950 gal/min maximum.
The average and median yields are 82 and 30 gal/min respectively.
Aquifer tests were conducted at various sub-basin locations to determine the
hydraulic properties of basalt. The Oregon Water Resources Department, the
U.S. Geological Survey, and CH2MHill consultants conducted the tests. The
aquifer test data yielded a range of hydraulic property values. Transmissivity
varies by sub-area and sub-area compartments, ranging from less than 50,000 ft2/d
(375,000 gal/d/ft) to over 100,000 ft2/d (750,000 gal/d/ft). Storage coefficient
values are generally less than 10-3 with most close to 10-4. Many of the tests
showed the influence of no-flow boundaries and/or responses from recharge
boundaries, leaky confining layers, or delayed yield.
Ground Water Flow
Ground water in basalt generally flows toward the valleys from the surrounding
uplands and then flows down valley toward or parallel to the Lost River.
Recharge appears to occur locally in both the uplands and valleys. Most
discharge occurs at fault-related valley springs within or near the Lost River.
Limited discharge occurs through the basin fill and stratigraphically controlled
springs above the valley floors. The occasional hot springs present are fault
controlled with water absorbing heat during deep circulation along faults.
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The geologic influence upon horizontal ground water flow in basalt varies. As
previously noted, data indicate four sub-areas exist in the eastern Lost River subbasin: south Langell Valley, Lorella, Bonanza, and Swan Lake Valley to Poe
Valley, and compartments exist within the Lorella sub-area and the Swan Lake
Valley to Poe Valley sub-area. Water level data show relatively small horizontal
hydraulic gradients (change in ground water elevation for a given horizontal
distance) exist in most sub-area valleys. This indicates low resistance to flow
within a given sub-area valley, even in areas with numerous geologic structures
and geologic units that are discontinuous or changing in character. Structures in
these areas are transparent to flow rather than impede flow. Steeper gradients
exist at valley margins, neighboring uplands, and between sub-areas, sub-area
compartments, and neighboring sub-basins. The larger gradients in these areas
indicate higher resistance to flow by the geologic structures and units.
The vertical ground water gradient within the sediments, between the sediments
and basalt, and within basalt range from downward to upward depending upon
location relative to recharge or discharge areas.
Sets of relatively concurrent surface water flow measurements (seepage run data)
confirm the ground water in basalt is hydraulically connected to the Lost River.
Free flowing springs occur within and adjacent to the river at Bonanza and
western Poe Valley. They respectively discharged about 60 and 20 ft 3/s to the
river in December 1997. Other springs located away from the river discharge to
the river via ditches and/or overland flow. Elsewhere, discharge from the basalt
to the river occurs as diffuse, low flow, seepage through the overlying basin fill.
Influences Upon Ground Water Elevations
Climate influences the elevation of ground water in basalt. The annual ground
water elevation trend generally declines during years of below average
precipitation and rises during years of above average precipitation. Additionally,
barometric pressure changes (expressed as feet of water) inversely changes the
ground water elevation at some wells with 30 to 50 percent efficiency.
Investigation data also revealed earth tides can influence ground water in basalt
causing the ground water elevation to fluctuate, generally less than 0.1 ft.
Canal leakage occurs within the sub-basin. It notably influences ground water in
basalt in the Lorella sub-area in mid Langell Valley. The elevations rise when the
canals flow and decline when canals are empty. In most areas, however, a canal
influence upon ground water in basalt is not apparent in the water level data. This
is because aquifer properties help dissipate the canal influence, and climate and
ground water use masks the canal influence.
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Lost River stage can influence the elevation of ground water in basalt. However,
the influence appears limited.
Ground water use clearly influences ground water in both the basalt and
sediments. Most ground water elevations decline during major ground water use
periods (the irrigation season) and recover during periods of reduced or no use.
Limited data indicate ground water near land surface in basin fill responds to
irrigation, precipitation, and snowmelt events. These events appear as short-term
spikes on water level hydrographs. The influence of these short-term events upon
ground water deeper in the basin fill is dampened and lost with depth.
Ground Water Response to Development
Ground water use in the sub-basin has increased over the decades. The ADR
permit condition D requires the Oregon water Resources Department to determine
whether “excessively declining ground water levels” have occurred due to well
use. The definition exists in Oregon Administrative Rule OAR 690-08-001 (6).
Water level measurements at nine state observation wells (generally from the
1960s through the 1990s) indicate ground water levels in the sub-basin decline
and recover seasonally and over multiple years. The seasonal fluctuations
correspond to the seasonality of ground water recharge and ground water use.
The fluctuation over multiple years corresponds to long-term precipitation trend
variations.
At eight of the nine sites, water levels during the late 1990s are similar to the
initial levels. Over a 40-year period, a possible decline of 1 to 2 ft occurred in
south Swan Lake Valley, Yonna Valley, and south Langell Valley, and a possible
3 ft decline may have occurred near Lorella. These declines are not considered
“excessive” as defined by OAR 690-08-001 (6).
At the ninth site located in southeast Poe Valley, a 20 ft total decline occurred as
two 10 ft steps, first in the 1960s and subsequently in the 1990s. The decline
resulted from local aquifer properties and compartmentalization amplifying
ground water use impacts during droughts. The decline is notable, a concern, and
deserves continued monitoring. However, it is geographically limited and not
considered “excessive” as defined by OAR 690-08-001 (6).
Under the rule, an “excessive” decline includes water quality deterioration as a
result of “ongoing lowering” of the ground water level. Periodic ground water
quality deterioration has occurred in the vicinity of Bonanza Big Springs as a
result of drought, seasonal ground water use, and management of the Lost River.
This situation is not considered an “excessive” decline under OAR 690-08-001
(6) since the deterioration is not related to an “ongoing lowering” of ground water
levels.
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Ground Water Drawdown Calculations
To address ADR permit condition A, this investigation calculated the potential
drawdown of ground water in basalt at the Lost River, Bonanza Big Springs, and
other springs due to pumping ground water as allowed by the ADR permits.
River and spring sites selected for the drawdown calculations were limited to sites
within the same sub-area or compartment as the pumping well.
The interference affect on the Lost River and springs due to pumping ground
water from basalt is directly proportional to the ground water drawdown in basalt
at the river and springs. Larger drawdowns cause larger affects at the river and
spring. The rate of ground water discharge to a river via springs and seepage
decreases as the ground water level above river stage falls. Discharge ceases
when the ground water level equals river stage. Then, the rate of reverse flow
(river water loss to ground water) increases as the ground water level falls below
river stage.
Drawdown from a pumping well at any location is dependent upon the pumping
rate, aquifer transmissivity and storage coefficient, distance from the pumping
well, and elapsed pumping time. Higher pumping rates, smaller transmissivity,
and storage coefficient, shorter distance from the pumping well, and longer
elapsed time lead to larger drawdown estimates. Conversely, smaller pumping
rates, larger transmissivity and storage coefficient, greater distance from the
pumping well, and shorter elapsed time lead to smaller drawdown estimates.
For each ADR permit, a drawdown was calculated at the closest Lost River site in
the same sub-area or compartment as the ADR permit well, a different site for
each permit. These individual drawdowns represent the maximum ground water
drawdown pumping a given well will cause at the river.
Again for each ADR permit, a drawdown was calculated at one of three springs if
present in the same sub-area or compartment as the ADR permit well. The
springs are Bonanza Big Springs in the Bonanza sub-area, Kilgore Spring in the
south Langell Valley sub-area, and High spring in the central portion of the Swan
Lake Valley to Poe Valley sub-area. The ADR permit conditions address
Bonanza Big Springs only. In addition to these individual drawdowns, the
principle of superposition allowed calculating a cumulative drawdown at the
spring sites, all the calculated drawdowns at a spring added together.
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The drawdown calculations included using continuous pumping at the maximum
rates allowed by the ground water permits and pumping at pro-rated rates. Given
the permits specify a maximum pumping rate allowed, it was necessary to
calculate ground water drawdowns using that rate. However, irrigators rarely use
the maximum pumping rate for the entire period of use for a variety of reasons.
Therefore, it was necessary to calculate ground water drawdowns using pro-rated
pumping rates. The pro-rated pumping rates were obtained by dividing the total
volume of water allowed by the total period of use allowed.
The calculated cumulative ground water drawdown in basalt at Kilgore Spring in
the south Langell Valley sub-area for 30 and 184 days of continuous pumping at
the maximum permitted rate ranged from nearly 3.00 ft to more than 3.50 ft
respectively. The total drawdown for 30 and 184 days of pro-rated pumping
ranged from nearly 1.75 ft to more than 2.00 ft respectively.
The calculated cumulative ground water drawdown in basalt at Bonanza Big
Springs in the Bonanza sub-area for 30 and 184 days of continuous pumping at
the maximum permitted rate ranged from more than 5.40 ft to nearly 7.25 ft
respectively. The total drawdown for 30 and 184 days of pro-rated pumping
ranged from nearly 3.10 ft to more than 4.10 ft respectively.
The calculated cumulative ground water drawdown in basalt at High spring in the
central portion of the Swan Lake Valley to Poe Valley sub-area for 30 and 184
days of continuous pumping at the maximum rate permitted ranged from nearly
3.00 ft to less than 5.00 ft respectively. The total drawdown for 30 and 184 days
of pro-rated pumping ranged from over 1.50 ft to over 2.50 ft respectively.
All the calculation results by ADR permit and sub-area can be found in tables in
the full report. Each calculation conducted can be found in the report appendices.
Conclusions
1. Ground water occurs in both basalt and basin fill in the eastern Lost River
sub-basin. However, wells with higher yields are generally located within the
valleys and produce from basalt. Therefore, this investigation focused
primarily upon the various influences affecting the behavior of ground water
in basalt including pumping and climatic events.
2. No “excessively declining ground water levels”, as defined in Oregon
Administrative Rule OAR 690-08-001 (6), occurred before, or subsequent to,
issuance of the ADR permits.
3. Long-term water level trends in basalt generally correlate with climatic trends.
An exception is a step-wise decline in southeast Poe Valley.
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4. Short-term ground water level fluctuations in basalt (annual decline and
recovery) correspond to annual pumping and precipitation patterns.
5. The study area can be divided into four sub-areas based primarily on the
behavior of ground water in basalt and in part on geology. At different
locations within each sub-area, the ground water response to natural and
anthropogenic stress is similar. Some sub-areas can be further divided into
compartments based on the behavior of ground water affected by geologic
structure.
6. Water level data from 1999 through 2002 indicate the impacts of summer
ground water pumping from basalt did not propagate beyond sub-area or
compartment boundaries during those years. This does not imply the subareas and compartments are hydraulically isolated or that any long-term
effects, such as year-to-year declines, from future ground water uses will not
propagate to neighboring areas in the long-term.
7. Ground water in basalt is hydraulically connected to the Lost River via springs
and diffuse seepage through overlying basin fill.
8. Investigation data indicate springs showing an acute response to seasonal
ground water pumping from basalt were located in the same sub-area or
compartment as the seasonal ground water use. For example, Bonanza Big
Springs responded to summer ground water use in the Bonanza sub-area only.
This does not imply that long-term effects from any future ground water uses
will not propagate in the long-term to affect springs in neighboring sub-areas
or compartments.
9. The effect of pumping ground water from basalt upon surface water is
proportional to the amount of ground water drawdown caused by the pumping
and the efficiency of the interconnection between the ground water in basalt
and surface water.
10. The most efficient interconnection between ground water in sub-basin basalt
and the Lost River occurs at fault controlled valley floor springs where basalt
is at or near land surface. The greatest ground water discharge from basalt to
the Lost River occurs at Bonanza Big Springs and west Poe Valley springs
located in or adjacent to the river. Additional discharge occurs at south
Langell Valley springs located away from the river.
11. The least efficient interconnection between ground water in sub-basin basalt
and the Lost River is through basin fill that overlies the basalt. Ground water
discharge to the river occurs as diffuse, low flow, seepage.
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12. High basalt transmissivities exist in the Bonanza and south Langell Valley
sub-areas and the central portion of the Swan Lake Valley to Poe Valley subarea. These transmissivities facilitate smaller, but very rapid ground water
level responses at springs and other locations within the same sub-area or
compartment where pumping ground water from basalt occurs. Even though
the water level response at a spring is small, the impact upon spring discharge
is large given the higher transmissivities and direct connection between the
basalt and springs. Most of the ADR permit wells are located in these areas,
especially the Bonanza sub-area.
13. Low basalt transmissivities and compartmentalization generally exist in the
Lorella sub-area and in south and eastern Poe Valley. These facilitate greater
ground water level drawdown when a well pumps from basalt in these areas.
Despite the greater water level response, the short-term impact upon surface
water is small in these areas. This is due to the lower transmissivities,
compartmentalization, and/or thicker basin fill making the interconnection
between the basalt and surface water inefficient. Fewer of the ADR permits
are located in these areas.
14. From 1997 through 2002, the ground water level in the basalt at Bonanza Big
Springs nearly met the river stage in the summer of 1997 and 2000, and
dropped below the river stage in the summer of 2001 and 2002.
15. Under current management of the Lost River, the calculated total ground
water drawdown in basalt by pro-rated pumping of the Bonanza sub-area
ADR permit wells is sufficient to terminate Bonanza Big Springs flow (lower
the ground water level to or below river stage) in most years.
16. Fewer ADR ground water permit wells are located in the central portion of the
Swan Lake Valley to Poe Valley sub-area where a direct connection with
High spring exists, and the south Langell Valley sub-area where a direct
connection with Kilgore Spring exists. In 2001, both springs stopped flowing
due the lowering of ground water levels in the basalt caused by drought and
increased pumping.
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